Office Appliances

Calculating Machines.

Where rapid addition, multiplication, subtraction and division are required, and no need for a printed record exists, calculating machines are used. They do not print a record of the items, but indicate the result on total dials., One type, known as the key-driven, causes the items to appear im mediately on the dials when the keys are depressed, the operation of a crank clearing the figures off the dial faces again. As with adding machines, the four arithmetical operations are all per formed as variations of simple addition. In another type, known as the key-set, the amounts are first set up on the keyboard and operation of the machine, either by hand or by motor, effects the calculation. The total dials, situated in the laterally moving carriage above the keyboard, show the total in addition, the product in multiplication, the minuend or remainder in sub traction and the quotient in division. Proof dials, placed in, above or below the carriage, show the multiplier in multiplica tion and the divisor in division. An extra set of dials is sometimes provided, which furnish an additional check for accuracy by showing the amounts set up on the keyboard. The dials are cleared by various means, distinctive with each make of machine.

For subtraction, the amount from which the deduction is to be made is set up, the operation of the machine causing that figure to appear on the total dials. The figure to be subtracted is then set up and the machine operated and the answer appears on the total dials. Multiplication is consecutive addition, though in some models multiplication is by means of a plus bar; in others, by means of an extra row of multiplying keys. Division is consecutive subtraction, some models dividing by means of a minus key, while another model provides for setting up amounts by means of levers pulled down to the desired numbers, this machine otherwise conforming to the key-set type.

A recent invention is a tape-printing calculating machine which prints the factors. figures and prints the answer and accumulates a total of all answers, all on a single operating stroke. It is primarily designed for accomplishing calculations in multipli cation at high speed (2o multiplications a minute) by a direct, single cycle operation, and to provide printed totals of resulting products automatically. It is equally suitable for performing division by reciprocals ; as an adding machine, it is equipped to subtract directly. The production speed, after the factors are set up, is uniformly 24 or 3 seconds per calculation (depending upon the timing of the mechanism) regardless of the size of the factors; that is, a problem such as 649,538 X369,486 is as speedily corn puted as 2 X 2. The decimal place in the printed answer is auto matically positioned. Its adding feature is not as rapid as with some of the standard adding machines. There are two keyboards with a capacity of six columns ; the product or totaling capacity is 14 places. The multiplicand is set up on the left keyboard, the multiplier on the right. The machine, being motor driven, merely needs the depression of the motor control to multiply one factor by the other and print them side by side, together with the product, in a straight line on a detail strip.

Book-keeping Machines.

The so-called book-keeping ma chine is in reality a device for posting on loose ledger sheets or cards. The amount is not merely entered to the account as in hand book-keeping—to be added and balanced at a specified period— but a balance is struck each time a posting is made. The original entry from which the account is posted is usually a sales ticket, credit slip or copy of the invoice. (See BOOK-KEEPING.) All such machines are designed to print and add an old balance, print and add debit items, print and subtract credit items and compute the new balance, in some cases printing it automatically, in others showing it in the adding and subtracting mechanism so that it may be copied in the proper column by the operator. Proof of the correctness of posting varies with the type of ma chine. One type is an adding machine which subtracts directly; it is equipped with means for printing dates, folio numbers, characters and abbreviations, and with a tabulating carriage which moves automatically to the next column as each amount is computed and printed, and in some cases returns automatically to any required position on the printing line. Both vertical and horizontal columns are added, subtracted and computed. Items are set up as on an adding machine, the operation of the motor causing them to be printed, added or subtracted. When a new balance is printed, the accumulator clears, ready for the next operation. Some models have two counters, thus making it pos sible to compute individual balances and accumulate a total of all postings. The keyboard may be split into two sections so that both ledger and statement can be inserted in the carriage and posted at the same operation—that posting being automatically repeated.

The design of a second class of book-keeping machine embodies a typewriter—on which any description may be typed—and a calculating machine, built as one unit. Some machines add and subtract in vertical columns; others compute amounts across the sheets as well. The typewriter carriage moves to correct column positions by means of a decimal tabulator. Typing the amounts on the number keys effects addition or subtraction. The amounts are visible in registers or totalizers placed either on the carriage truck, in positions corresponding to the to be added or subtracted, or at the front of the machine below the keyboard. In posting, a new balance is computed, and the oper ator types in the proper column the amount appearing in the register which functions to compute across the sheet. If the typing is correct, this register clears. Ledger and statement are made at the same time, in some cases by means of a carbon and in others by the split-platen method, one machine of this class being unique in that its typewriter section is mounted on a carriage which moves from left to right across a flat printing surface on which the forms are held, a back and forward motion providing line spacing. Registers are mounted on the rear of the typewriter section, and ledger and statement are posted at one operation by means of carbon.